Dnmt3a knockout in excitatory neurons impairs postnatal synapse maturation and increases the repressive histone modification H3K27me3

Elife. 2022 May 23;11:e66909. doi: 10.7554/eLife.66909.


Two epigenetic pathways of transcriptional repression, DNA methylation and polycomb repressive complex 2 (PRC2), are known to regulate neuronal development and function. However, their respective contributions to brain maturation are unknown. We found that conditional loss of the de novo DNA methyltransferase Dnmt3a in mouse excitatory neurons altered expression of synapse-related genes, stunted synapse maturation, and impaired working memory and social interest. At the genomic level, loss of Dnmt3a abolished postnatal accumulation of CG and non-CG DNA methylation, leaving adult neurons with an unmethylated, fetal-like epigenomic pattern at ~222,000 genomic regions. The PRC2-associated histone modification, H3K27me3, increased at many of these sites. Our data support a dynamic interaction between two fundamental modes of epigenetic repression during postnatal maturation of excitatory neurons, which together confer robustness on neuronal regulation.

Keywords: DNA methylation; Dnmt3a; H3K27me3; brain development; epigenetics; genetics; genomics; mouse; neuroscience; synapse.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / growth & development
  • Brain / metabolism
  • Brain / physiopathology
  • DNA Methyltransferase 3A* / genetics
  • DNA Methyltransferase 3A* / metabolism
  • Disease Models, Animal
  • Histone Code* / genetics
  • Histone Code* / physiology
  • Histones / genetics
  • Histones / metabolism
  • Mice
  • Mice, Knockout
  • Neurons* / metabolism
  • Neurons* / physiology
  • Polycomb Repressive Complex 2 / genetics
  • Polycomb Repressive Complex 2 / metabolism
  • Synapses* / metabolism
  • Synapses* / physiology


  • Dnmt3a protein, mouse
  • Histones
  • DNA Methyltransferase 3A
  • Polycomb Repressive Complex 2

Associated data

  • GEO/GSE141587
  • GEO/GSE47966